Cardiovascular <3

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Transcript of Cardiovascular <3

Cardiovascular <3The Cardiovascular system -- A closed system of the heart and blood vesselsThe heart pumps bloodBlood vessels allow blood to circulate to all parts of the bodyThe function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

the HeartLocated in the thorax between the lungs; Pointed apex directed toward left hipAbout the size of your fist

Coverings:Pericardium – a double serous membraneVisceral pericardiumNext to heartParietal pericardiumOutside layerSerous fluid fills the space between the layers of pericardium

Semilunar valves – between ventricle and artery• Pulmonary semilunar valve• Aortic semilunar valveHeart Valves -- allow blood to flow in only one direction• Valves open as blood is pumped through• Held in place by chordae tendineae (“heart strings”)• Close to prevent backflow • Four valves

• Coronary Circulation• Blood in the heart chambers does not nourish the myocardium• The heart has its own nourishing circulatory system• Coronary arteries• Cardiac veins• Blood empties into the right atrium via the coronary sinus

• Cardiac output (CO)Amount of blood pumped by each side of the heart in one minuteCO = (heart rate [HR]) x (stroke volume [SV])• Stroke volumeVolume of blood pumped by each ventricle in one contraction

Regulation of Heart RateStroke volume usually remains relatively constantStarling’s law of the heart – the more that the cardiac muscle is stretched, the stronger the contractionChanging heart rate is the most common way to change cardiac outputIncreased heart rateSympathetic nervous systemCrisisLow blood pressureHormonesEpinephrineThyroxineExerciseDecreased blood volumeDecreased heart rateParasympathetic nervous systemHigh blood pressure or blood volumeDecreased venous return

roadsMajor Arteries of Systemic CirculationMajor Veins of Systemic CirculationArterial Supply of the Brain• Hepatic Portal CirculationCirculation to the Fetus Pulse -- pressure wave of bloodMonitored at “pressure points” where pulse is easily palpated

Blood PressureMeasurements by health professionals are made on the pressure in large arteriesSystolic – pressure at the peak of ventricular contractionDiastolic – pressure when ventricles relaxPressure in blood vessels decreases as the distance away from the heart increases

Capillary ExchangeSubstances exchanged due to concentration gradientsOxygen and nutrients leave the bloodCarbon dioxide and other wastes leave the cellsMechanismsDirect diffusion across plasma membranesEndocytosis or exocytosisSome capillaries have gaps (intercellular clefts)Plasma membrane not joined by tight junctionsFenestrations of some capillariesFenestrations = poresDevelopmental Aspects of the Cardiovascular SystemA simple “tube heart” develops in the embryo and pumps by the fourth weekThe heart becomes a four-chambered organ by the end of seven weeksFew structural changes occur after the seventh weekBlood -- The only fluid tissue in the human bodyClassified as a connective tissueLiving cells = formed elements (RBC, WBC, & platelets)Non-living matrix = plasma erythrocytesleukocytesErythrocytes -- red blood cellbasically sacks of hemoglobin (Iron-containing protein that binds strongly to oxygen)44% of blood

Human Blood GroupsBlood contains genetically determined proteinsA foreign protein (antigen) may be attacked by the immune systemBlood is “typed” by using antibodies that will cause blood with certain proteins to clump (agglutination)

ABO Blood Groups -- based on the presence or absence of two antigensType A -- the presence of antigen AType B -- the presence of antigen BType O -- the lack of these antigens A & BType AB -- the presence of both A & B antigens

Rh Blood GroupsNamed because of the presence or absence of one of eight Rh antigensMost Americans are Rh+Problems can occur in mixing Rh+ blood into a body with Rh– blood

Blood TypingBlood samples are mixed with anti-A and anti-B serumCoagulation or no coagulation leads to determining blood typeTyping for ABO and Rh factors is done in the same manner

Leukocytes = white blood cellsCrucial in the body’s defense against disease0.5% of blood